SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '609623f86308e5a484ade3ebe85cf13583ccdd650e13bd156bee7d57b994e27a' 
  AND token = 'tPWbguJNhQ1sKBVHwdoI8un0QutS9ius+supLyeUgS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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