SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ecfae24f9ba316fb352f3a90fcf3ae921e337599372cef491575f0618488c44' 
  AND token = '72pfk7N9QZAGyc5OkSeKMFLTxfCEVADOKY3AQi4ZT4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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