SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a6dca205965f9220267421e7d5300f2d422f4092ab81a5cad8ad137521c7d455' 
  AND token = 'RcI6EUhYQZoTl2EBXFUI81tRSmRfuy+1yR68cQ5aYLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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