SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2393b7781a86315b7198377d0d3ca5ddef6abeff98d815a4a889aabead7cbf18' 
  AND token = 'o2vTeNChvnqBoVT4YBV03wWervIMwgx/XmQhEUUzwXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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