SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93911d0d8ad68e669fcbbe59284ef8f05ec2b20350ceedaa4a254523eb40df58' 
  AND token = 'kN8/enMfZeOQz4nUFf1pV7SVMbiVNDzYi3LYU6qJxWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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