SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e5771665b40d5d82056219183ed4ae6619959df00fe5bab3bb09474fb3e2df4' 
  AND token = 'JStQlUahe2YSg/M/hnHXXqoM5m5r9TurY8WxjS9aMNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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