SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '408d3eca3765eb472ec17e5086b8bca953b8e7f0defd87cf45e55a3e9f50a3e2' 
  AND token = 'eipo9/whE1I+eHYEG2nTOOKRLyx4vDBUIFVcJjw81d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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