SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c5c82efa251aea568463b26e5f9b123095f380e44944a6477749f338433558' 
  AND token = 'vENnE6VmvLwJPMtsKwlqtAU2JggpU4o7oOKDChl6ufw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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