SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '111a3eba9f7d701afb933b9f5f269d55f42d846aabfa20bc46259bb122a4c509' 
  AND token = 'ypqMSaS38++LzxMVSLslVBhm2MZoWYSYMfVGkSpnpuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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