SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c415e58680bf2d5b72e1fddcd173a0684b8202a3f176d7134d1a92f4f3a7756c' 
  AND token = 'vQc8bIXMr6fSVKLpMFcDvhcm7wGEbQ+VxE9YBkPpAUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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