SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '120d2b5496f59afe15b5c3a111199bb69973d32b612a752cfa876948e1ea9d59' 
  AND token = 'dm4cdHz8LPWbtP98FnF/KZqKntOGraaAh+okOe/cSnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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