SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0ef5bce7751fe9bf09bb96d6ff06b174fcfc5963d6dcedec0d2ed84737bbdc' 
  AND token = 'J9bz5GvB5R79RH41cS0OxAFPo9ZQo6knaqfSEqZsaLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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