SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a0a1016ada1e36cb51052e42e7d71be90c897cc3e668a9a70d39a2498da18a4' 
  AND token = 'cSbGtjIG5iDXLOlZZPZ9z1420CgOSxyftFGl974/akQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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