SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c7953a8191c730947b0cd5d21aef15d90415e3df323ad0f44a399b021acabf6' 
  AND token = 'I7WYkUA1cYp/nK8nyg86v4sUjQJSZ5L+/pOzH9XCS1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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