SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '373c74cbe6f2713fb897aa458e6c2fa187e8458d08805fb0629f7c9988a2bdf2' 
  AND token = 'GyUxd4ySOO1z08kr8fJWXCoeLcuOFmZ8urbzC2XhdIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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