SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f432b1055346d8a30445fc524da88be0bf7d7122ecfd8bed6e78a80c774c0c' 
  AND token = 'ZG/OZPZ+36lb4hrwRgJJFRERGqxyCCFbqlTQ/8Rl9ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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