SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fbc5dc01ecc5dc40b78a9b2461859284d4e2099cb7826fcd201c0930f407af03' 
  AND token = 'rHqSiU+TDRdF8Q7U8WpR/Nyo7ZT28cJRiW7AWg6SBl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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