SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd772b59a35a38cbe39733945202c02b5ececb50f7f12402e5034a1be6e62e5c1' 
  AND token = '2O8YGSojuNFBIPBmPUnCZSIQ5vg8yqmKevDothno8jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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