SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c7f25104e3ec348f27a8d3bf02b37138987ee60630e22de5fdfdf04d5665f20' 
  AND token = '+w1xmgVBWscqYj1XbPmtIUppv4HmBZszBwP1MG0VI74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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