SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2310fe9f246393bd7bf12dc710d6d0a961747468c35da8eec7d3ce8c747ccabe' 
  AND token = 'OEoNzZH0Mbdkis+E3DlPbHbqEI5yYeKbRikWa22rd6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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