SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e32b3ecdb82770264eb7401705e286e6f897546778660838cb4f6d92c5d71839' 
  AND token = 'AnuUHJdSbCPvD+b9L0vR5NfRoA+SuFC02fPPQyzCTTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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