SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da9985a82704bc99d1b936842e738a3ddd59de01f3e206815d2a963d87058f0f' 
  AND token = 'cNoIkhokorrc6h0JuYl0fiGmwQwbnKEJBNT/aQ+a8Aw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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