SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a64959c4eacb3847c1fd4a1695224bf9e0faef7cd789bfd9684e3c397e90854' 
  AND token = 'uJKRnmlsDcBwzBlraF+eVeNSnVYJ445VyrYe2DIhgp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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