SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7ac99bef2786ccc7e4618918d8bb31e44e37326da50f24f880ecfd017be39cc' 
  AND token = '/SrOH8BlFTk+FrAE6DupUFyGB0SUGH5XzIiWU0ZFkqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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