SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f17154dde5ccce103d602fabdaba995067e068b0e716569d2e15a8aaff58ac8' 
  AND token = 'uKr9yNW+wmIAaluKDzPadQui1nXVERrP9W7kTNaWW6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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