SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a9f0eb8b81b4e6d6a853e94fd9cf57617415bb1f82882d705a77de905d9b54' 
  AND token = 'Z8REKfe6QHoBORGcgdJEha6puQ2mOWtLKZiBhFQje1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}