SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5d0aa407339efa55728f8fb0915820e67b494d6d31e702516be37417cd759d4c' 
  AND token = '10ukvZ9/paqTxzCdUVxjZk+GvxvkjcyqV4HjeEwOCQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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