SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a559bd18674984f22aedadb2344728eafc9a310ea9734a9f640ce6a5f0463611' 
  AND token = 'msZvRzQU65JYhdLmJdQ3YLEG/1O28fqvB1bdHAVXpYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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