SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce9f15df6f06ced6119229571919302cd05f8abd53ec21b4a6fd37951a0e9c8' 
  AND token = 'h3yUsEljgKirYYlBYVbZeoLdTlwJso1RT9BhL/1SE4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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