SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06ded462407a3a4c388f3e9f15ff5bd6eb607a4c913937ad8bd5b4d0b8bfbf57' 
  AND token = '65froVJf9XfDfxkfhxRjgSB6TGPbSosbWhUg8UVJC2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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