SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d34c3e6906928959d14bc2a17eb15927eed51f803b8184ee785e9156490f6ab' 
  AND token = '7Wq8v8kbCAkKF1+VHqOFZev0WBp2S2JK2QkexUyFkt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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