SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955a351d0d43370330c731091b0558ecfdbe8f7b3bb4e6050ff4463c81602fd5' 
  AND token = 'mlYm5y3jHEgqMxXsfEwTuAW3IKOEZ9fj/sg3qONcJcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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