SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5f52dabd3f733d370a43654c98e16899abd3561334b0f7f4ddc5a51a8822b3' 
  AND token = 'GT97Aigb4jHb1HR2f/6bwvPFOZ5zBb5nsmRAKJ01DQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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