SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b112ce6f142f6ef394d67c37edb4152b58e2f1a0c39f6ee6e3a84b51941fdbec' 
  AND token = 'i6uQbMWzRMMGXvuxmtWVNMkULDCzUfz8JFtqBGAanaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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