SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fa84d4d068dca2aa776ea2e6f5b13bd8cb604baeef4733510cc1476cf8ce14' 
  AND token = 'gaqx+QYVi9IGBpSHpIpm9/ulZ85BhVLCeP+QLzjSjUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}