SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a13461200c8e608cc91043625742b18b8206b752b6db86365afcbda9a1b86f' 
  AND token = '+EKgqLykVdFcMD7IVOrYLVUSxh0Yqrz0zxIc9r7fZ9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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