SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3572416472bb43fe032922acde5392e6cee3bc4f328d35fd1a0cd63e8e94203' 
  AND token = '7C5DsL/XBNXSXBzARLyfTXrYGV45SvsVGM/RA0mObMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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