SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da7cadd821c1e954b8c5f6143e8c150fc30851695a13fb3c5379825828eab270' 
  AND token = 'bExLzuQfdhb83TQWMwcHaMP5uzCmXj4OgLaiRcfVNyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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