SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3b6526485c5433a1bff8827e5778cf2e9d2a7ea63112e6e36186748f55516bb8' 
  AND token = '0J3D9Z1CL2O+/7SCytaUKSfm+IMGDmo7zYUfgOc3UhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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