SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8911b4ad76b405975fb44a8a1ea422d08e1b2247cfc1c70bef36f3b4f85590b1' 
  AND token = 'LzzMjn+F56EXk2fhFQTAh5FnaM4hS1JvYUNLT059tQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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