SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dfda5c1a28109c7be673ff2c2f7c0eb115a57a9a80af728a3518c3acbcc5e5a9' 
  AND token = '2pirLV2zSiUlXk78baBR5ecyJ66nkIXmiyJkwRRaXfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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