SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192336afbf4961b989fb8c0589cb36359279084e82f139ed639ebce9e3c5fb8d' 
  AND token = 'uR6H/r4LX0rXfkUWgRVliDqnNm16pQu8OEdOqiW+T5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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