SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c47b5b5e50bd80db59d741efa8b6f124a82d86b3ca6d4b138b823525f420536' 
  AND token = 'RIJ2veBA67pv33Ri6eUGGWVMFdmarU4yRht9sv2rNpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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