SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2bc213aa4326e781ad4e5eb7743942c8a38eb20bc62dc1805cf9d35f4e2dda96' 
  AND token = 'Q/ZiFsLvBv1YRS7SY1+xP0Kys5pHNHEl7AH6L2Vrhk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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