SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '754faaebef2dc5bf121238dbfb666f0d756127ec81e84363b4db12c4d802f808' 
  AND token = 'oh9vo0Xr6APgwxJjLHT+p1t9gVamQU3xQXD6IMZRF+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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