SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30f291ad52bd8358bbae95babb41235745f521e78d39f744c7283fb68aaa6856' 
  AND token = 'GAxTZH/mVrOVS3ts++A5kVWX+ZVUwHpNPSVCSuvYp0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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