SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15963dd0cf334af8a4528ae837e275adf756a1ebf0c0a3a9b45547c5d950e44' 
  AND token = 'lSg6M44HT3dLFJcmr3J8IXOdfdqB1IpmJH/KNcIkOcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}