SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06bd1e6f902d1ab466bcc898757066ad8c8bc697204e9deeab1a5824c462c359' 
  AND token = 'z5NdpWI+PZ0yZY2JnRpgqXjVakLYn/YDoc1k90STIuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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