SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '854c9a351a7e948914991562f8251138a07d5ab3b4d9a6dfab644d3a5243eb81' 
  AND token = 'pk8m2EUQpvFNfV9x953ZBwbkxkor/8fSQQv0jK8cbPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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