SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c2520aede9990ae752401d37a46a70ca9d98b3a82f762958b5fca74d753ee7' 
  AND token = '1xd/JbODcqcisekz8GcQgTZvbQwud25vjdr0WqTvhtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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