SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a83daeebdd625a5b6a76a225e7bbea6167091cf2ac034a0835ff74f2d120cf95' 
  AND token = 'AsDAIwFlugsHaGircc9CBUlFWo1U/EV3wANsXZoaRVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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