SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b52ea7d71150db530508fd0c18c5a6b0600c5ae1eff9f7c542b4d41e16074b3' 
  AND token = '4H86R+SKkuP3l6q5qExXQOQzkt2+//49S9oIM7bUV1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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