SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc06d06e0aeba3f4088aaa0dbac4c97bc1ffd9a63dc7410f576ea31bcf250114' 
  AND token = 'Tm35CiNQMwoM8gWzfimKGSMMHTT1EHP66ra1flT/Zak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}