SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6eb9074929b8983ac883b9573edceb48c7784010f6cbc9ed69a020950e3c2b9e' 
  AND token = 'FH07yic+sVFTuHF3NxCqixZQWfmIScyMJTE5Npv3NQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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