SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c6204640f3911cfbd1341c685727429685c89c9f83b62f2462871f484d8f0d6' 
  AND token = 'woWkQIZ2uNdEej+JBbkYpidxcv7LgdvvKRRRERHKmyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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