SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '156a46a3eb094e54d6400dd93e591eba7150815ea7b636b701b1bbd8bea0b31c' 
  AND token = '3vAUubPTbT/xnE82eH1oHRyGjkeC+TtnTrU3jAVK/rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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