SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7efb4364242d91b891aea10c4a6d05d37624186fb9279e2123e135a3d8f30e61' 
  AND token = '3QEY39WUQIq7kgjs37BCkKUzYoViOP5tijKSjUUKm58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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