SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17168d6eb34086f1709ffd020077f9d1205de93761aec5dbb9acd5f8e1d80966' 
  AND token = 'uOX3X8sMc39TRm0NKUvqt9KveSfkLiNWGb/3zQpjZpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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