SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727d81c50b43242f91628499ae56f547f91baf40ef3efd86f05af4b3ff3f388c' 
  AND token = 'edOHWLxJT+6kjcgx+4hxU2wIG3qo/qiDKuj1A1ft2ZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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