SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f216f1c707bff3d1e073baf4a102687d5ca57dc2f218f1c462b11f25559489' 
  AND token = 'nDsifkXBvY+ddJav36pJ7ZGnWzjbT98hD3xqqU4h3zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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