SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3735537ff3238d7dad26de605806fb9c61b49cfb97b6b9eeb9201a52391d6f3c' 
  AND token = '1gTkA0dmTE7zhT8OGpwBe1wMJSxb6435KQdOgleZNb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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