SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17e6b44c5ffaec2eb9af42dd342c4994aad30b369fc713832ea4859b254618ab' 
  AND token = '0kPVoil7eZP1AEzjXuYA9Ojd6qTzhNKA+q7+OjFw9vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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