SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ca011842dfe91fdd99953b067cf0d8465f03878e9b7afb53ac5bbc45f0b9a59c' 
  AND token = 'hztBVRMXYf0HzlikiG45ppNO8OYLHWIRk0KeP+d9Cts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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