SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cc2f3404dd026fdea8701ca082fe8e5d35bb78efe9cce9bfbfd373f91f37be6' 
  AND token = 'cFWI41I6xD5IqCPyn2SgPMo+LpLv6JJvRCylHegNx2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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