SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a75e36695175a4b47aec269c5d73116d93c6cebec5586b8df0497eef9e6d8af6' 
  AND token = 'Y7XGXieJQoJmT2STx4dX7h3vTiS1PuZwDB/YKMYgqVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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