SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ae41e76a9fd41713228bde4a9bc83c2446b0f267139a07a961aa70632c1c47c' 
  AND token = '3PRIop5VRejVKO342NhIyzZx5f5BUZ4w4Ku0OtM7DqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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