SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '774d1755a53751167526ef8e50f6517dd4eeeb983343d68406d7581e731b72f1' 
  AND token = 'BLjIY6lrP4Y9LPGRjn1Xdw6sAHAsBLtCLK1c8vubTyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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