SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88e7af7bdb6f0f99149e76c89368418aa124fe27538f8e7ecbd17a2f00715ef6' 
  AND token = 'bYrNAXUNwjhXpgC/VK59oh/5VFrXEIFYO8kBwnQCosE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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