SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3914217d4ca85fde252df1568cceb56245ac79e08681f1beb4f0325ea77d06' 
  AND token = 'OGBwDmuAqse1ljcVZ+4FFLMFJxmg2Ei9unuEdo21EZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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