SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c0bfd3aaca528822d2e894afe43d0db280cecc68cbbff456e810dd85eb99af9' 
  AND token = 'kds/X0yYg5lvnBBb/picymBL0RL7JenUCdxaKNIIpvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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