SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e141fabbc1d44ea941418043edecc1d2afc99eb4becd2242f839cfd35daa56e8' 
  AND token = 'wGb1tBchx3Ww9gygMXFkDn0ZkzKtZJ9JsHhP+qy438c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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