SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb63eab6e644e395648e94a4bbba0b481eb4243b95be23f9baca211095d1cae' 
  AND token = 'tLQbP4OP3rRhMi3qCUvY56v+5ta5eChDDMT+ntoYB2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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