SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '349cb88ac20d568e7441b51c9873111dfd2b8bee4a46c6aab84146845a3a73ae' 
  AND token = 'JJXtyJIvhrJ/WBqaBL/3obIuZ25AMiZv/Uue3f6tifg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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