SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52fc7d42dbaa0e89ddc850bb8379bb5deafe9f7287a87bbf174f5d6941d1b4c6' 
  AND token = 'tLolq7YosIhVmOXvmkkYeVvyymkPBHS6AFGKOn5FJNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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