SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6765ad86b90c6c99c2b0fbaf6638e85dfc3dc5fafa58c25ba6245723ef196f79' 
  AND token = 'cRSzJBI96PAoBPKgd63gJYR/ZQGUlAS6Y+o70VB/2bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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