SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcff5995d60c4a3dd7a155a1ff4b2689b1367629b29b42062cb08a8799bef644' 
  AND token = '61Gv6JNlblozvSpk8okw+GVjF4CQlPhuqknRHzSfq4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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