SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a061cec60d2004cf274d0aaa6c7def5860b10573a7bde86249f1f2449866d5d' 
  AND token = 'PCZGawwZ+JylAlJCwJNYi8yPtMzfPcD+l5ZSqpicKuo=' 
  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"
    }
  }
}