SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8359458da90ef8deb9fd7aa0537e6bfbccff871d5d60516360ed8492069d3c' 
  AND token = 'LrCPQlh4MWS2AuoCOVFKgx6bACZ4GfC9RN4T9BssxZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}