SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac1f82abcb4f8369f8d4914dec3d16ee648658f01c529c1ae79fc7972219a43c' 
  AND token = '0PrKsiz8iYJcYrEoGHrVApGK9hGlcMb29zQCYJeIrcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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