SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dd796c2bf46f833ba82e27b37049012750c3391f2968155717365e202223a80' 
  AND token = 'v7GwvrWbgRpHZ4aFc1/SpQ24vNTsGKZKjpLfp9wO0qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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