SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '942294fb900a95c6d712df9f01fff7641d4c111c5f0d7d98dcc1d7c726ea5665' 
  AND token = 'u5Bcn4hOvYQVuUPVNmacusGLJOoF/Y3+nwvPP4qxpg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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