SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e715597ff590ea665904be6ff8b4a746b4b51b1e801e3dc695629b6d7342a15b' 
  AND token = 'I/7tyl4pKsWNZcowNEmQJXlvjjHNAmsg97HUdBjtLT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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