SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '140c9d3c05a7bc19e8d771a963258ba77efe8ba541e2603422448144dbec9423' 
  AND token = 'ujlKjGT2PMZTUjRfdMRZznLuCrvonztovQr2kgSxYs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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