SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '49115d3a0baa7d886742dd72fdebe225089edf060267507500b530dfc2ca8d80' 
  AND token = 'KewRyPSPy6S0sBIBvx6M6H6SeixDx3/FjpdsklNBzbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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