SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6429918af277e6541f720299e265280cc2752deef055e5a76733e548ad1232bb' 
  AND token = 'HsmOUdagcOtpoJEp4el2BdD/lINMt02dpjDj0Z3HH+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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