SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '412d09929a86684484ee7a98261255cc550c019bb61c9764253b1039eea3d087' 
  AND token = '+McWMl/9seXgddaiUV/jeS44ZscmNWLS/cQyGsTVAt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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