SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f3b78c8eef49e54b92f9136711ed71f19b0e0fdda8c6988e9f9ca4e56c23f61' 
  AND token = '0hEZaGkq7W+damAsHrKLjGaDQDzjLnlpUBhRrSj+/LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00219

JSON explain

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