SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '724ab130b260d506cc555491995e6d364e1a22a7d3183d1f1a5570a06030a94f' 
  AND token = 'q1O5bKgIKzT080LoEMRWCzXR+nhLdUpjiBMWaHzdzZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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