SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '167be8f948611ff4ac56cd90bde4b2e81409e9e17e96edf7b4167b571eecbc28' 
  AND token = 'BmUcOQhOcxhYGRwjyKxqllV7KS6PmZgvF/Ybt7c54VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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