SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bebd897fd90c7561376b2388df9493b8aac1d8054de44b724c665243ab5355a' 
  AND token = 'kCG0LKTxDJ4adwIxrUFHNmcj0m8YLrNmFKGSgGQPKA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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