SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '385a6cdfbfd6a6b45beaf36bbdcc85aba91407aad2bf3249c6101667503fb112' 
  AND token = '9IhuKw57ryk/D4IYrlbVxE1qdEkRuKJGTdJ9pelu2zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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