SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3302db3f963213686628e8f324c5511fa580c10db7fdaecf7e9fb207a55d4c93' 
  AND token = 'Wwe96+mJXHnD4N8RrGOqLz6vlVOhl1pBgp9F+hruMgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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