SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d72056eee207a18711521ef3d9f824cb569e3a1be84841353c406fa3ba8b95' 
  AND token = 'RXPyzlZfUfyfus4jw+x7WQzC/YFLKnsm8hLjTYEpTOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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