SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6fadb600ec6317a82e93356c9172ba704ff9f7c3e0137fbc6ef6295b76880d8' 
  AND token = 'bGzvNDaMqpJMr00rZIaGN+Z+fwjvWmGMOrAqpTyMoRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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