SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65fc1aec0fa718d3d45a4c193a4fb0b5cbaffc9a035cd701125f0805e2d3fd51' 
  AND token = 'CZNIWmvNzW+u2qjLn1JITPIa2w7elA6meBTP0bOrtIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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