SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0533a9104a65ac6311c0c7a98a8f0d2e89744237ffbb31ddba5655a104260938' 
  AND token = 'JGpiRY46KDWYTFrmXrfD3dtvcy3ZDrcTEODIs8JhcCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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