SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e39757239c15c0bfb61b4e8aefa72ad0f8a7b4d29f7b4203da083327274d9f4d' 
  AND token = 'VASySfAAxXE1kvdrf1zgNe+RMMkuRc0k2OZDyqyONDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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