SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f4420511565279fd45446edd28d72cdf36f28bfcb9199b396b870936e81d57' 
  AND token = 'D2Puw9pRjugq8qd/PRHiMmA9PAPm0CG/+xkBdP6eVpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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