SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49be8ecdf7eb3642deea5561adc6e8cc00d9c7a4f590b523d1210863b46bb87a' 
  AND token = 'SruNDwC5NVwCAKJcnGOQbeBi0XpLXneTbAnYkjKUeEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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