SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbefea58a95345d12b795dd64cdee4d19123b72bfd6573a4eb57f70ed8f3f450' 
  AND token = 'xcp/No/B2zqnj5GnGi4DjzzEhwAJvM85SXdq0UKCMkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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