SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce87f0f85190316ae8e9177f2bcbbebba4434675fd97da2dc5830f0ee014d4a' 
  AND token = 'GehqOeEdg3f+/dC0q23Nj+vBgBzdFYlUmA1oPgxV8j0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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