SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7bf10c929eaf6c3546f389b63e625e6ac81e1adf12c1b9cc474ea01609e322' 
  AND token = 'jJtV0+nSdvROlh+vH1lrybyiMLrkiotsAdUtrgrGKz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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