SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96038682b07ed1308bf49013cdf359d91ed01f284290df5908d811a5986da909' 
  AND token = 'JCHiM40AIZ0atwn6kNiQIeR8AzvBnBE/F2beavcutV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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