SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab62be52687bc6481f8bbfdd31ce28f6c856fe59cc3fcd543ad77221bd39d71b' 
  AND token = 'mgr1RNUYk4xAVKTXTF3WABoqnKOtGwno/TPih9MxzGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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