SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '929b21f4a7a7fc46225c6a7384f226450584ffbbdc34d37f012e6744c03f09f7' 
  AND token = 'V9kLJThVRWW40Ak+hYYLh6erFyb4OIrrQ7rzxSuxGzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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