SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d2fc325a1ea71b8cc6eda806eab7e7fbb4acca7cb5bb328ca5544caad40cf2' 
  AND token = 'WqJoq/3Fl+jhLK87+MLMhKq4ccUmiGseAGDWOPBHNu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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