SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b76c961f50f71ba92c79b2d45853ba2f5db64ce95a195a002d685187086c186' 
  AND token = 'MAfcqMOUsEHVZIILSDo/zBjoYY+umQkGFVWt0f4ItaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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