SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c5a8c186fc6b556b40195116429d46eb29224bcbe09d0511cf5c685af3eb87' 
  AND token = 'blRBq6J/yvsZujOTotpLP+hIiKW+bGeYzNYAolX8HS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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