SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6e72797c9581d8c6463e4c8878ec6677fa2872be97868d58428ff2e5fa26b71' 
  AND token = '5IeyM+hEngMMuJPY16GyXKhTyn7bYSun3ZiUA8kj0ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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