SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6595423396ccbe3e4f21cf65783ad05cc4e44e6eaebecc8c423e3bdd3815aea8' 
  AND token = 'tUQMq5IlqGc7j+hZe0GuGGhlj0+Bl5AIvZIkPNcA9F4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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