SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b8223d7d862b1238ff1e1a266bc23fa9e856dc24aee405cb017201550b18040b' 
  AND token = 'PQonJD6Ai0n9h72kz5Y/6MsNtiqq5aCLcO/5VtruPf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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