SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac9a04ffd96f072b48c9ca96c3f41cca43ac4ddf054f4a2090d4399f1988fb2' 
  AND token = '2BE3mmwWcNhgGmvHKoKLpEx/Vp4MjQnnV4EgOoFxkas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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