SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a58eb11c6412753eec056bcfd37f85b3decbd714ba4b6a1b91cf80f25f8156' 
  AND token = 'ywD3l+nL6tdPQhFXzqYXBZIjQEjYN2Xr8vuzYOfL0EE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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