SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e2d98f7404e3951c8e929228310b74e0e581d7a2f1303f6740ef253b6e4d3b7' 
  AND token = 'MeR8rL51EaB6tQL6srtgzZxbQSCderv6DSQdp52rE2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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