SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f29a6e0eaf6e00869b3f716264318c735b084bd15db2d80621af28c087b2841' 
  AND token = 'ZTAMVbH+QxBhMvawZBZur0kcFUFH5ilAqpwi9CFHb9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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