SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd1fa0318b15d16454554e28c4d079202474b548a8d322e91208d839fa93972e9' 
  AND token = 'j42cyqAIwbZdfQnZ9UKm63h3JUfGaYlca2Wj1Kx90AE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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