SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6e5bdea19e1f9a62a20e11c81b4cf25225532c3f1131d987319798334a1cd200' 
  AND token = 'wdIGEse/VHzkeeQMtqewoeNS4UtJSou8iHEPmIfxFxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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