SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49067721945d8a69b1b696d5e13e48612b16c8f527e39bc3999ef23ee131ae72' 
  AND token = '7JKVl/H8u6ZmPaFNPosCdCBspHNzU3mKf/uZ6RfgZ5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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