SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2e3206b1efe57375020f1f2c0d8c36bc6b9569b79324554dc5945085c56684b' 
  AND token = 'tE2ZzxS+R0G6uUhETm/7VzPnMcm4iJDMcjd/iBgWTNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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