SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aab0c51f706e20a523d20433cff9dbddc247dd5ec8e994f1a494ae86c1b919f4' 
  AND token = 'T+eCEaQOPvx7lpzu3oDGPJ1euskTwDFF4Q9CQVkIzYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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