SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7136e2b62a3f3da4f7256c3fa7e6caf487d53cdb4848706fad296aae918dafca' 
  AND token = 'oiTEWIOZ7fu703uI7c5B58Poivinon7NsMEfjrxxqY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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