SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ae759e2aa911e49a22d4fd18b186ed4d32875ac89b593618404a4a0908a140' 
  AND token = 'Dz8tB9TS2iY7PyWWcO3yFgLBBbqw4f4Kys4dP7mEtZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}