SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a289ee268f8816583ce51afc5435ea569ec3381838e357f4c99216069c3c40f8' 
  AND token = 'ZfdClqviwI7jds6NvxWVcKAD8SrTKVB11zpxNBrps+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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