SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2f6ecc2f4f07451d5a90db167db020a4775b7430edda91db821caa46b8ed5e' 
  AND token = 'vZ2RHNw8Q9JWgS+fYg0Zry3G2jWlQKOasbXz8hRYV10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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