SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ae48c1109d9546736a9ed58533b25ac78175b056b22674c53ecbce8f4217929' 
  AND token = '73i7DKNxWO9eEbj8lMn9t3xL/mKCEj6q91CKA5h6/Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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