SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdc011c7235cd8b246ed50a480fd40960536e7910463281bb419549a72e3101c' 
  AND token = 'tT0Uq7lNtEOy6gd1nUFjGb2YChAN2gfZvOsm8KID9GI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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