SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c051f8efb41d7cbc47c39956228eeecacd9533fe1d75f61d883c969bbc6ea7a0' 
  AND token = 'itmnG1PAZmqNQMv5avwpE40CNcO2wtTTUiUsPXF92g8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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