SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1df8157c0ffa020ee4bca8388d8619d14e18f6b4908a5fddcb7b384d1d5268b1' 
  AND token = 'nMWzckOOptjeYxgQOTlJKcf5WwRMtu7Gqil8QlaRJKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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