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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6c3dfda7b8eeec9160a2bce2bf0231fa5d68b6b35c46230a038555cf60d9745' 
  AND token = 'qtXv4Gc3j7uJ2OwmpB8HrfK7K55Bvf43heEM17zMt9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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