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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de8c286e75fbd52c960f747e5d09e81c24d2d37fdfb00efdbd2ec701162e76bc' 
  AND token = 'hXiO8R82NumbFRbocci1zFhsV9T1OemsoIndhDAYR90=' 
  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"
    }
  }
}