SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7509039db496b68e962a6e1fe799afa458dae5fca49ebd9c59adaf559b8ae555' 
  AND token = '/BLnBGk7BnDVnV1o0xyWCA5BbFhEjjHXX228orXInWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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