SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '769a22739e336f24e3f661b358ed8b05d2daac4548ef4f845da65949c22543dd' 
  AND token = 'PHbLUVNYhGlzJGso/jRGMCF+k9UIK3HuGwiiqRqSR7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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