SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11a6c3765497ff947373fff05126835c10ebe43bc9b70f688399fa6e55af56c' 
  AND token = '1MsZ1YeOBslMwyTHGa/SpDzNTxOvCHaqczh2y22bMFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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