SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72f6178fb3cbb5c315ef8da9a0c55edcedc69741d08543f68a261fb032a1cb32' 
  AND token = 'MQGEwMsiFbUfc8DoWZd9nogPBoDKyXe1sJYRYtSkHMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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