SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f69e820cb681dbda99877be9b8172291dadc7092054faa7b0659d424d507091' 
  AND token = '7FQO7YTT2Y3JOTnkiB+NyFjgzNAvZ8TzOxrwhI6y0LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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