SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4537163642217afc633b7ec01b6c81628f10a6aab9163d74537a3f875ef51f1' 
  AND token = 'HXqgJmI5zhmvxJ07poH4mvdXVB4WnrCkqwSc0/TIlIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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