SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b6842ae540ecca49be54ea3ed5ab45498433608f971699a26edddc6dacd2bf' 
  AND token = 'Sp8AFqUK12IZYsGy3IkYQm/Rh7310dcqMlZ8NGWP6zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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