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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e65323b9c8eb1de19e69b9a290269feeea4cbbb7ea5b2d98eb215ed16c976779' 
  AND token = '6asUrJq31IHzrgqDsGHo1Sw5JdrGo1ZQARpEdN7SiSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}