SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590cc9a81ac2d7367aa85a9542c56ffe97f9a9869b9cbcb991640b5da647b039' 
  AND token = 'GSucqjU/GuOFDDJZ2ERNafAdPah86fmxtVQmieBk9k0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}