SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ce7a723387ef1dd816d260a66215e668241c3742357bd6dbd271d4a421b4361e' 
  AND token = 'afSu8C9PdUSImCxU6gi+Gex4O+mguxnBlXBKNlQyPhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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