SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7ead7b13d9ec010911739365bb589c0fa6aa331cf5153262a8625d91857b5a97' 
  AND token = 'qJZ2CWrDGQlmjAFwFje0zS+4Oot3cTYJWsf6Q512RdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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