SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08e2fe2658b831d028234ce60115397e3fffec2a004036a55e3be5b9bf2f2de0' 
  AND token = 'SpVw4W7zRTqt8OwXC1cd5DZFORy9PNd6poYFD92glZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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