SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19bd1b0142bae28513119ab9da4e7a1b01684fa95c59e5fdbe20b91936b874c7' 
  AND token = 'gVBMk/awUzDPFPqflVHGHTyIryYf162Wgvxl6mbZX7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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