SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4adb25b58f708fd2abf6072b0eb651400583c4cadeaad69cd26836d3452df48b' 
  AND token = 'Lmkd+sgBxebfT1XR0fFlJuW96JK9CElXgmtBSmz4Wms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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