SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3803543850905a9771c95cf536b1766f8b338493ee1ed985e9d8c779b74dfe25' 
  AND token = '7/O7FMHjVVj/rCBXu254jqO2q1UhiYxgF3clNWGRL6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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