SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '548b55a408fbf5f55050902b6d78619cc3691f301d2da91bd1d163280dbf6cfe' 
  AND token = 'Qiu6ZCCl15WxLz/N8m4k6H01c19HB//yHNYbts1/zf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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