SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88261e640294a3668035ff2bf6ff453b51fb0a15214295f75d8d6427db6ab350' 
  AND token = 'tIXkLecfwchBTyjhSNtfFhAraaxphYuW9Ua6YteyRoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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