SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '039cd915496d608bed5a509be625ddc7e7f6b439d6a9baf25c9ba9812e25124f' 
  AND token = 'yCj7Q9NNcKP+4nH7xbsLYmtUjIgJrrCGBqDPDYoy08g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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