SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89238e2c439318885927d21018dc740457007a607525511558bd5bab0bbfe09e' 
  AND token = '9XwK5f39PZva5XzLSeV7l6rh+qxgfP0kYO302IUfA90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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