SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '223a62cbb2a7c53c91d43652bffcd6a4f8bf31c87b78b893a79811703c22d984' 
  AND token = 'LmdJAxUrgO+jz1DXzqyXZ5v2LKyKl8skRo3RQRFsVKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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