SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e19889b0397fd08fe0669a83e12bafad675824806b195c2bf6a44f5d5e551e1' 
  AND token = 'Zyuvq4RzFP5bSm3vtXdzgoYRaCXxG6ki/Stcxgr6l8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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