SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c9463801a54702479a2cff18bbe1be65ed12344515fdf89acdecd3baa933217' 
  AND token = 'cmsERhEbK0dq1jRAU9DdT7JcuF/gkvXZApGGwWxw/r8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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