SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c51355aba4ae959124110f1dcecf48dee7ab938441194c94c9cc12b32298dd62' 
  AND token = 'LNpbpggS9xu/PGx2vtQTTQwwE6d9Ui4bgPjmPl6Va0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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