SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4567b89b22c5ffbdf4394dc6ee26a23f3cd21a37362474c70735628e1d12612' 
  AND token = '76nbOB+TrDXteyaMBTea1GPvLUhRfj8co0rksIvgka8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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