SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8c39d6db389515f242e7004e9e1338725fa031ff9f711c0e437078fe47ed627' 
  AND token = 'MBByyznx04t6Gu8wPktfWmKtGCUH3T2W+zYc8tZbSKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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