SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e34662158f1b26ab60d15f5181f8497bace24430e5d43737296286b16de643f1' 
  AND token = 'RO4y7wfTkjEW4ukTsesZcIoVkxUMmH5SbgSkArRdQEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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