SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '27dedbab4df81bb500aadd6e84170b77f7aa8f2f80925dfb6698a366730ecae9' 
  AND token = 'h2vtwMfC5yopcznhNDHpZB4JPgvYL9FlcPODbWNM0ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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