SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75d77c79e756b2a22aadda160f70c1508affea14a4f27376d1fee03cb4ab14f1' 
  AND token = 'aG8bM3CdC0Bgwlm5nE6Uo7E912549dCN/kzrU/6aLDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}