SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484e50154c6167509c5c854e5a6755f1b7c4798e4e1aa1589e0b1b114def6372' 
  AND token = 'trxb6D+BKv9BViRsbVMaMeclkz+BCKpNR/mtI4aHxLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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