SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a6482f80d3c0f0d8610401144589428a71936986195853b9c2c74963c257e37' 
  AND token = 'Imjgyo8pjTGYMXtqu6ZKwUdtY2TUO+3ba9JUKXmzDTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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