SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c813382ae002fcb722f9b938639812aca1c9ceb78e51e56416541bf52e0fb8' 
  AND token = 'q1Jxa8rOXGkjJ6EnVwxxJ3o6pKOp/C7doERhYrc0XDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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