SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5da8d3f99b738e143c8ba458a1cbc3a7bc86754646fdd68fd0eebc8068bed341' 
  AND token = '6G7ciFXyUnwgQGCp/SdhLUNoO3a08zG3XsmdHBc/D6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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