SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a4a47ece48decee11c16b27548ed01a5c6256b95ad037fc87161cf56f7ef3e' 
  AND token = 'Sxwb8WxC46Tz/1ePGSTutq2LzhPDaB/RKMlZU5BBJ/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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